This project is designed to study the role of proteolysis in cell synthetic and growth processes. We propose two specific approaches. The first is to test the hypothesis that proteolysis is involved in the synthesis and assembly of multienzyme complexes. We propose to first study the complex, fatty acid synthetase, to determine whether it is synthesized on one or more mRNA molecules and whether proteolysis is involved in assembly of the complex. It is hypothesized that such complexes are proteolytically cleaved in a manner similar to the proteins of several animal virus classes. We will test this hypothesis with methods previously used successfully on animal virus mRNA's. The second approach is to study the action in vivo of the specific in vitro inhibitors of proteolysis, TPCK and TLCK. These drugs have been used to generate a number of important results in transformed and nontransformed cells. The results are concerned with the specific control of the growth of transforeed cells, the inhibition of co-carcinogenicity, and the post-translational processing of uninfected cell proteins. The validity of these results rests to varying degrees on the specificity of the drugs. These studies should prove useful to further study of proteolysis by use of specific in vitro inhibitors of this type in in vivo situations.